The moon is the Earth’s sole constant satellite, and there have been several tales about the impact of the lunar cycle and spikes in crime rate, moods, and sometimes even psychosis. The most common association, however, is between the lunar cycle and sleep. Studies suggest that it does, in fact, affect sleeping patterns, and according to The Guardian Trusted Source Lunar cycle has distinct effect on sleep, study suggests | Sleep | The Guardian Research finds people stay up later and sleep less before full moon, and do the opposite before new moon www.theguardian.com , people tend to sleep less and stay up later, right before the full moon.
Previously, the correlation between the lunar cycle and sleep mainly focused on women. However, a recent study published in the journal Science of the Total Environment and conducted by the Uppsala University revealed that the influence was more powerful in men compared to women. Some of the reasons why previous studies produced conflicting results was because most of them were chance findings. Most of the past studies also failed to control their research for critical cofounders that have a significant impact on human sleep, including insomnia and obstructive sleep apnea.
There are 2 periods in the lunar cycle; the Waning and Waxing period. The waning period occurs between the full moon and the oncoming new moon, and the illuminated area on the moon becomes smaller. On the other hand, the waxing period is the phase between the New moon and the full moon. During this period, the area on the moon surface that appears illuminated as seen from the Earth becomes bigger every day. One of the study’s corresponding authors, Christian Benedict, who is also an Associate Professor at Uppsala University’s Department of Neuroscience, revealed that the study’s participants involved 360 men and 492 women. They used sleep recordings from one night at home and found out that during the waxing period of the lunar cycle, the men whose sleep was recorded exhibited more time awake at night and had lower sleep efficiency compared to women, who, interestingly, were unaffected. This study was adjusted to accommodate obstructive sleep apnea and chronic sleep problems.
Some recent studies also suggest that the reason for the above findings is that male brains are more responsive to ambient light compared to women. They also suggest that the impact of the lunar cycle on sleep is caused by the sun’s reflection on the moon during the time when people go to sleep. However, this theory is questionable because, on average, the moon’s luminance is only about 7% of the sun’s brightness. This intensity is fairly low, especially because people are also exposed to artificial light at night, that’s far stronger compared to the light reflected by the moon. According to the Washington Post Trusted Source Moon phases may affect sleep, study finds - The Washington Post A new study observed that people, on average, can take about 30 minutes longer to fall asleep and sleep 50 minutes less on nights leading up to a full moon. www.washingtonpost.com , most people slept an average of 50 minutes less and took almost half an hour more to sleep before the full moon.
Another theory suggests that sleep variations are caused by electromagnetic fluctuations from the moon, which affects the Earth’s electromagnetic field. Some researchers have also suggested gravitational pull, which is highly unlikely because the lunar cycle does not impact gravity. While there are various theories as to what causes the variations in sleep during the lunar cycle, the only constant is that the waxing period does, in fact, affect sleep quality.